The two flash drives differ in capacity and form factor. The Connect Wireless Flash Drive is basically a thumb drive with a microSD slot. The Connect Wireless Media drive is a square (about half the size of a playing card) flash drive with a standard-sized SD card slot.

The idea behind these drives is wonderful. You can purchase a mobile device - a phone, a tablet, whatever - and use the wireless drives to supplement their onboard storage. My iPhone 5, for example, only has 16GB of capacity, so having an additional 32GB or 64GB is great.

Neither of the drives comes with internal storage. The Connect Wireless Flash Drive comes with a microSD card slot and an included 16GB or 32GB card, depending on which one you buy. The Wireless Media Drive comes with a standard SD card offering 32GB or 64GB of capacity. Both work wirelessly via Wi-Fi (802.11 b/g/n); no Internet connection or router is required.

SanDisk's 32GB microSD card for the Wireless Flash Drive

The Connect Wireless Flash Drive has a slide-out USB 2.0 connector that works like any thumb drive. The Media Drive comes with a USB 2.0 cable. Yes, USB 2.0.

USB 2.0?

Therein lies my first knock. Why use USB 2.0 when USB 3.0 -- at 5Gbps -- is 10 times faster? Using outdated technology means that when you're downloading movies to these drives, you'll have time to go out and grab some popcorn and a drink. Uploading an .mp4 of Star Wars (1.81GB) took 5 minutes and 12 seconds. (The larger Connect Media Drive, however, almost halved the upload time; it needed only 2 minutes, 28 seconds to upload the movie.)

When I tried streaming Star Wars to my iPhone 5 from the Wireless Flash Drive, it took more than four minutes just to load and then paused to buffer a few moments after play began. After that, it streamed seamlessly.

I then tried walking away from the flash drive with my iPhone in hand, and after about 100 feet, I lost the movie stream. The worse part is that after losing the stream, I could not reconnect - not even after shutting both devices down and rebooting them. So, even though the flash drive's antenna is supposed to have a 150-foot range, it's best if you keep the flash drive on you at all times when you're using it.

SanDisk's Connect Wireless Flash Drive

In contrast, Star Wars loaded onto the Wireless Media Drive almost instantly and began to play. I was also able to walk up to 150 feet away in several directions from the drive with my iPhone 5 as the movie continued to play unabated. Clearly, the Media Drive has a more powerful Wi-Fi connection than the flash drive, even if both are listed as 802.11 2.4Ghz devices.

Both wireless drives contain a lithium-ion rechargeable battery that can take up to two hours to fully charge. A charge provides up to four hours of wireless streaming from the Flash Drive and eight hours from the Media Drive, with streaming data protected by Wi-Fi Password Protection (WPA2).

Movies, music, photos and documents can be loaded onto the wireless drive by simply dragging and dropping the files, which are accessed via the 8.2MB SanDisk Connect app. It's available for download from the Apple App Store, as well as from the Google Play Store and the Amazon Appstore for Android.

SanDisk's Connect Wireless Media Drive

SSD is the way to go

SanDisk's wireless external drives are its first, but they are also an industry first in that other mobile wireless drives are based on spinning disk. SanDisk's use flash, which is more resilient for mobile use because it has no moving parts. For example, earlier this year, Seagate released its latest mobile wireless drive - the Wireless Plus. At 0.8-in. x 3.5-in. x 5.0 in. and just over half a pound, Seagate's drive is considerably larger than SanDisk's and is based on traditional hard drive, spinning disk technology.

Ironically, when I reviewed Seagate's wireless drive, I wrote that the "one thing that might make this drive better is if it was an SSD." Well, SanDisk made that happen.

The Connect Wireless drive family allows users to not only store, but share and stream files across multiple mobile devices. The Wireless Flash Drive offers up to eight simultaneous device connections and three media streams, and supports separate streams of 720p video content at 2MB/sec to three devices concurrently. The Wireless Media drive offers up to five concurrent video streams.

According to a SanDisk spokesman, video streaming performance isn't affected by multiple streams because device limits are set at a point that supports the streams without degradation. Devices can connect to the drives up to 150 feet away.

The Connect Wireless drives both work with all iOS and Android devices, Kindle Fire tablets, as well as PC and Mac computers. The drives are compatible with Windows XP or higher and Mac OS 10.6 or higher

Besides size and capacity, another difference between the SanDisk's Wireless Flash Drive and the Wireless Media Drive is the user interface. The flash drive has a lackluster text menu while the Media Drive uses large, colorful icons for its photo, video and music files.

The Wireless Media Drive's user interface for iOS.

Conclusion

Overall, I love the concept of these wireless flash drives, but if I had to choose between the two, there's no question I'd spend the extra money and buy the Wireless Media Drive over the Wireless Flash Drive. Not only does the Wireless Media Drive come with up to twice the capacity of the flash drive, and it offers more concurrent video streams, but its Wi-Fi works more reliably.

The SanDisk Connect Wireless Flash Drive is available in 16GB or 32GB capacities for $49.99 and $59.99, respectively. In the U.S., it is available for pre-order on Amazon.com, Newegg.com and Micro Center, with availability at Best Buy starting next month. It will also be available for pre-order on Amazon.com in Germany and UK.

The SanDisk Connect Wireless Media Drive has a retail price of $79.99 for 32GB or $99.99 for 64GB storage capacity. It is available for pre-order in the U.S. on Amazon.com, with availability in Germany and UK in the fourth quarter of 2013.

I'm hoping that SanDisk gets the kinks worked out of its flash drive, however, because its miniscule size makes it attractive. At the same time, the Wireless Media Drive is completely pocket-sized and just as portable.